1. Technical Field
The present invention relates to elastomeric or rubbery pipe connectors for coaxially joining a pair of rigid pipes having two different diameters, and making the joint in such a manner as to be readily dis-assembled and leak-proof. The connector has particular utility in joining the drain pipe or hose of a washing machine to a standpipe or the like.
2. Discussion of the Prior Art
Washing machines typically provide for draining of the wash water by including a flexible hose with a section of rigid pipe attached at the discharge end of the hose. This typically U-shaped ("goose neck") hose pipe, usually having a diameter of somewhat more than an inch, is inserted into the open end of a vertical length of drain pipe connected to storm sewers. The drain pipe diameter (typically either 2-inch or 1 and 1/2-inch PVC) is larger than the diameter of the discharge hose pipe, so the hose pipe can be inserted into the drain pipe without interference and rest therein under the influence of gravity.
The goose neck hose pipe is shaped so that the discharge end rests several inches down inside the drain pipe. When the washing machine pumps water out through the hose, the water usually runs easily down the drain pipe; accordingly, no fluid seal between the hose pipe and the drain is provided by the manufacturers. There is nothing to hold in the hose pipe in the drain, except gravity.
However, the velocity of the water discharged from the end of the hose pipe into the drain pipe is sometimes so high that reaction forces, caused by the downward blast of water, lift up the hose and blow the hose pipe right out of the drain pipe, resulting in a flooded floor. Problems also occur when the water discharge speed is not great enough to lift the hose by reaction, but the drainage is inefficient. In this case, back pressure added to the reaction force can force the hose out of the drain pipe, or, the hose pipe may stay in the drain pipe but the water backs up and overflows.
To alleviate these problems, washing machine installers devise connectors from makeshift clamps, cable ties, etc. None of these jury-rigged connections is practical, and the washing machine blow-out/overflow problem remains unsolved.
The common use of an outlet box does not offer a solution. Kifer et al., in U.S. Pat. No. 4,410,004, describe a laundry drain outlet box having a connector at its bottom capable of fitting two common sizes of drain pipe, or "tail pipe". The connector fits one size internally and the other size externally. There is no means provided for preventing blow-out or of holding the hose pipe in the drain pipe.
In the prior art, connectors or adapters made of resilient material have been used for joining rigid pipes.
U.S. Pat. No. 3,913,928 (Yamaguchi) discloses a resilient connector for coaxially joining different-size pipes. The smaller pipe is inserted into the larger when the joint is made. Yamaguchi's connector comprises a generally tube-like annular cylindrical section adapted to fit between the two joined pipes in the overlap region: that is, the connector is of such internal and external diameters that it presses against the inside of the larger pipe and the outside of the smaller pipe in the region of overlap. The connector has annular ribs or fins, on both the internal and external cylindrical surfaces, to seal against fluid leakage between either pipe and the connector.
Ribs, flanges, annular sawtooth ridges, and the like, are often molded into pipe fittings for sealing. Separate gaskets are also used, as shown in U.S. Pat. No. 2,778,390 (Young).
U.S. Pat. No. 3,998,478 (Zopfi) and U.S. Pat. No. 4,293,138 (Swantee) teach connectors that are very similar to the Yamaguchi connector. Zopfi employs only internal ribs leaving the outside of the connector smoothly cylindrical.
In U.S. Pat. No. 3,680,896 (Cupit) there is disclosed a series of ribs or serrations molded into a flexible connector used for coupling water closets to sewer pipes. The disclosed toilet bowl connector has two ribbed sections of different diameters, joined at their ends. In one embodiment, Cupit discloses a doubly smooth-walled cylindrical section of resilient tubing for sealing against a pipe, there being no ribs on either the inside or outside surfaces. The end of the unit is connected to an accordion diaphragm. The length of the smooth-walled section is just under 0.8 times the radius of the section (as measured in drawing FIG. 3).
A "sealing sleeve" for water closet installation is disclosed in U.S. Pat. No. 4,547,005 (Soederhuyzen). The Soederhuyzen connector has two coaxial tubular sections of different diameters the smaller diameter having external ribs, the larger one having internal ribs. (One embodiment lacks the internal ribs.) Attached to the end of the distal larger section is the thin-walled, cylindrical sealing sleeve configured without surface ribs. The sealing sleeve is attached by an annular bridge to the larger section. The device is molded in one piece.
The smooth-walled sleeve has an internal diameter equal to the internal diameter of the smaller section. The sleeve is inverted and disposed within the larger section, so that its end distally of the bridge aligns with the end of the smaller section where it attaches to the larger section. In use, a toilet bowl outlet pipe is inserted into the sealing sleeve; the outlet pipe is thus also disposed within the larger thick-walled sections, surrounding the inverted sealing sleeve. The space between the sealing sleeve and the larger section is empty, and no part of the connector touches the inside of the outlet pipe.
The function of Soederhuyzen's sealing sleeve is not immediately clear from the patent. Soederhuyzen apparently relies upon the differential in wall thickness between the larger section and the sealing sleeve for the proper functioning of his invention, which is directed toward ease of toilet bowl installation. The material of which the connector is molded is specified to be "resilient", but the only material named as suitable is polyethylene, a relatively rigid plastic.
U.S. Pat. No. 3,148,895 (Jasper et al) discloses a connector for coupling vacuum cleaner hoses onto the cleaner body. The connector has a triple-wall construction with the outer skin being vinyl and the interior filled with a "soft squashy substance" like sponge rubber. The outside surface is cylindrical with ribs, and the inside has a stepped series of concentric cones with special indents adapted for vacuum hoses.
U.S. Pat. No. 4,779,904 (Rich) teaches a stepped series of concentric cylindrical sections used in a connector for vehicle tail pipes. The cylindrical sections have ribs for internally sealing an exhaust conduit.
U.S. Pat. No. 214,991 (Coler) discloses a flexible connector made of rubber for coaxially joining two differently-sized pipes. The smaller pipe is disposed within the larger pipe in an overlap region. The rubber connector includes a tubular section of such internal and external diameters that, in the overlap region, it fills the space between them. This interstitial tube section extends along the outside of the smaller pipe, beyond the overlap region, a distance about equal to the overlap distance. The end of the larger pipe is thus disposed near the middle of the length of the rubber tube section. A bridge or annular flange extends radially outward from the rubber tube at this point, joining the tube to a second, larger rubber tube surrounding the larger pipe along the overlap and the interiorly disposed interstitial length of the smaller rubber tube. The inner tube, the bridge, and the outer tube are all one molded piece. The larger pipe is gripped both on the inside (by the outside surface of the inner tube) and on the outside (by the inside surface of the outer rubber tube). The surface bearing against the pipes are smooth, i.e., without ribs.
In U.S. Pat. No. 4,758,027 (Todd) there is disclosed a cylindrically symmetrical member consisting of a stepped series of tube sections. It is easily molded because there are no protrusions, and it appears to be made of rigid or semi-rigid materials.
U.S. Pat. No. 2,025,067 (Miller) shows a funnel-like device for filling auto gas tanks. One of the embodiments is made of resilient material. The device has a tube adapted to be inserted into the gas tank inlet pipe, and has at its upper end a series of ribs, all coaxial or concentric with the tube. The internal diameters of the ribs increase with distance from the upper end of the tube, so that any of various standard sizes of gas pump nozzles may be inserted and form a fluid seal with the particular rib matching its outer diameter.
The above references do not disclose a connector adapted for use as a washing machine drain connection. Specifically, none of the connectors described above is directed toward coupling a washing machine discharge hose pipe to a sewer drain pipe, and none is directed primarily toward preventing blow-out or separation of the joined pipes. First, many of the disclosed devices place ribs, flanges, or bands against the pipe surfaces instead of smooth cylindrical surfaces of significant length. The ribs are intended to increase the fluid sealing capability of the connectors; however, fluid sealing is a secondary consideration in a washing machine hose pipe connection where blow-out prevention is the main goal. In order for a elastomeric tube to best grip a pipe, the surface contact area should be a maximum; this implies that the gripping surface must be smooth, not ribbed. Second, the cylindrical gripping sections of the known connectors are short, again decreasing the surface area and reducing the gripping force. Third, the connectors known previously depend upon only friction to grasp the connected pipes; they use no method of increasing the force beyond that caused by the mere initial assembly.